Tactical detachable anatomic containment device and therapeutic treatment system

ABSTRACT

Devices and methods for the controlled delivery of therapeutic agents into bone and soft tissue to prevent the unintentional migration of therapeutic agents from the treatment site. The containment device can be made of a fabric or membrane that is porous, semi-porous, non-porous, bio-resorbable, or non-resorbable materials. A containment device is advanced to the interior of the target structure and filled with a therapeutic agent. The containment device may be permanently or temporarily implanted. Where permanent implantation is desired, the containment device may be detached via a severable junction.

FIELD OF THE INVENTION

[0001] This invention relates to medical implants, and in particular, todetachable containment systems for implanting therapeutic materials invivo.

BACKGROUND

[0002] Numerous bone conditions or spinal injury can cause painfulcollapse of vertebral bodies, including osteopenia (osteoporosis),vertebral hemangiomas, multiple myeloma, necorotic lesions (Kummel'sDisease, Avascular Necrosis), metastatic disease and complications fromsteroid and non-steroidal anti-inflammatory drug (NSAID) use.Osteoporosis is a systemic, progressive and chronic disease that isusually characterized by low bone mineral density, deterioration of bonyarchitecture, and reduced overall bone strength. Vertebral bodycompression fractures (VCF) are more common in people who suffer fromthese medical indications, often resulting in pain, compromises toactivities of daily living, and even prolonged disability. Likewise,degenerative and injured spinal disk rehabilitation (pharmacological orgene therapeutic) protocols to delay the progressions of intradiscaldiseases, or even to restore disk health and disk functions, are a partof contemporary research developments and emerging standards of care.

[0003] The science of spinal intervention has made great strides inrecent years. On some occasions, spinal or poly-trauma patientsexperience VCFs that may be repaired by vertebroplasty and other spinalreconstructive means. Vertebroplasty, which literally means fixing thevertebral body, has been used in the United States since the mid-1990sto treat pain and progressive deterioration associated with VCF. Mostoften in this vertebroplasty procedure, a bone cement, like opacifiedpolymethyhnethacrylate (PMMA), or other suitable biomaterialalternatives or combinations, is injected percutaneously into the bonyarchitecture under radiographic guidance and controls. The hardening(polymerization) of the cement media or the mechanical interlocking ofother biomaterials serve to buttress the bony vault of the vertebralbody, providing both increased structural integrity and decreasedpotential for painful micromotion and progressive collapse of thevertebrae and spinal column.

[0004] Bone tamps (bone balloons or Kyphoplasty™), a contemporaryballoon-assisted vertebroplasty alternative for treatment of VCF, alsoinvolves injection of a bone cement into a mechanically created bonevoid within vertebral body. In this alternative vertebroplastyprocedure, a balloon tamp is first inserted into the structurallycompromised vertebral body, often through a cannula. The bone balloon isthen deployed under high pressure. The expanding balloon disrupts thecancellous bone architecture and physiological matrix circumferentiallyand directs the attendant bony debris and physiologic matrix toward theinner cortex of the vertebral body vault. The balloon tamp is thencollapsed and removed, leaving a bony void or cavity. The remaining voidor cavity is repaired by filling it with an appropriate biomaterialmedia, most often bone cement. In most cases, the treatment goals are toreduce or eliminate pain and the risk of progressive fracture of thevertebral body and its likely resulting morbidity, complications, anddisability.

[0005] Although most of these interventional procedures are animprovement over previous conservative treatments that consisted of bedrest, pharmaceuticals, and/or cumbersome back braces, these methodsstill suffer from the complication of potential leakage of thetherapeutic biomaterial repair media (bone cement, etc.) outside of thedesired treatment zone. Numerous risks are associated with these spinalinterventional procedures. The risks and complications, which arerelated to the leakage of the biomaterial into structures that areintended to be preserved, may involve extravasation of the biomaterialinto veins and/or lungs, infections, bleeding, rib or pedicle fracture,pneumothorax, increased pain, a range of soft and/or neural tissueimpingement, paresis, and paralysis. Most clinicians prefer to focus orcontain treatments to the injured or diseased tissues alone.

[0006] Disease and injury can also erode or violate the supporting andcollateral soft tissues. In the case of an insult, disruption, disease,or injury to a joint construct (spinal column [e.g., spinal facet], hip,knee, elbow, fingers, ankle, shoulder, synovium, collateral ligaments,etc.), joint capsule, ligamentous structures, or cartilaginous (collagenbased) tissues, it may be necessary to manage or contain physiologicalbiomaterial, or other therapeutic media within the joint or anatomicstructure. Likewise, primary and secondary spinal tumors may contributeto a loss of tissue (bony, etc.) integrity and strength. Therefore,these tumors may serve as indications for vertebroplasty and otherinterventional spinal augmentation. The treatment of many other diseasesof the bone and other tissues can also be facilitated by treating thediseases from within and/or proximate to the target anatomy. Forexample, chemotherapeutic agents could be implanted in proximity to orwithin a tumor. Or in the case of a failed bony fusion(pseudoarinrosis), a reoperation and revision may be avoided through theintroduction of biological agents into a containment device designed topromote-bony healing. In particular, bone healing by interventionalmeans may be facilitated by the implantation of osteophilic(osteoinductive or osteoconductive) materials, which are scaffoldsand/or materials used to stimulate or optimize bony healing. Thesematerials include, but are not limited to, hydroxylapaptite (HA),tri-calcium phosphate, biocoral, bioceramics, biomaterial granules,demineralized bone matrix (DBM), bone morphogenic proteins (BMPs), andcollagen. Bone morphogenic proteins (BMPs), an active ingredient in DBMand a member of the TGF-β (transforming growth factor-β) super family,mediate developmental processes that include morphogenesis,differentiation, cell survival, and apoptosis. Although the role ofTGF-β is not fully understood, its net effect is an increase in bonematrix. Other factors, such as insulin-like growth factors (IGF I andIGF II) and platelet derived growth factor are also important.Unfortunately, since these proteins have short biological half-lives,they must be maintained at the treatment zone in sufficient therapeuticconcentrations in order to be effective. Therefore, dilution of thetherapeutic agent due to the unintentional migration of the implantedmaterial away from the therapeutic zone is also a major challenge togood patient outcomes.

[0007] Accordingly, it would be desirable to provide treatment systemsand methods that contain and deliver implanted biomaterial or otherpharmacological or treatment media at any time during the treatmentcycle, while preventing the unintentional migration of the implantedmaterials and/or controlling the release of the implanted materials intothe targeted tissue or cellular treatment zone.

SUMMARY OF THE INVENTION

[0008] This invention relates to medical implants, and in particular,containment systems for implanting therapeutic materials in vivo. Thecontainment device of the present invention is especially appropriate,but not limited to VCF treatments. The containment device provides abarrier, preventing the unintentional migration of its augmentation,reconstructive, pharmacological, and therapeutic contents from thetreatment site. In one embodiment, the containment device is anappropriately compliant, mechanically expandable, or self-expandablecontainment structure that can be filled with selected therapeuticmaterials. Alternatively the containment device could be made of asemi-compliant or rigid material, as may be the case with many spinalfusion implants. The material used to construct the containment orchanneling device may be porous, semi-porous, non-porous,bio-resorbable, or non-resorbable, depending on the therapeuticobjective. The material may also be made from a continuous material withuniform properties, a fenestrated material, or a material having avariable thickness to achieve specified geometric deployment. Thecontainment device may have many shapes depending on the structure to betreated and the intended therapeutic effect. These include, but are notlimited to, a “pouch”, that can be sealed, a “stent” to channel ordirect the therapeutic material, an elongated “sausage”-like shape, or aflattened “disk”-like shape. In addition, a particular embodiment mayinclude a double- (or multiple) nested containment device, where thereis at least one containment device nested within another. Thecontainment device may be filled with a variety of therapeutic agents,depending on the therapeutic objective. In the case of VCFs, thecontainment device may preferably be filled with a bone cement, such asPMMA or the like, or an osteoconductive or osteoinductive material. Inthe case of tumors, whether in bones or soft tissue, chemotherapeuticagents may be injected into the containment device.

[0009] In a vertebroplasty operation, the containment or channelingdevice is inserted into the interior of the vertebral or other bony bodythrough a hole in the exterior of the bone. The device is then deployedinto the interior of the structure and filled with the desiredtherapeutic material. The device can be deployed by a variety ofmechanisms, including response to temperature change, mechanicalmechanisms, or deployment by a suitable gas. Alternatively, thecontainment or channeling device may be self-expanding, assuming itssecondary shape automatically upon release from the delivery device. Inthe case of a VCF, the therapeutic material utilized is often PMMA orsome other bone cement. The device can then be sealed, using a varietyof methods, if desired.

[0010] Depending on the therapeutic objective, the containment orchanneling device can be accessorized accordingly. The device may bemade detachable where permanent implantation is desired. A wide varietyof detachment technologies are known in the art. Preferably, anelectrolytic detachment technology, using a braided catheter, may beused to separate the containment and delivery devices after thecontainment device is filled. The device may also be retrievable whereonly temporary implantation is needed.

[0011] In addition, the containment or channeling device may also becombined with other external or internal systems to monitor healingand/or stimulate therapeutic responses. For example, some device andenvironmental controls may include, but are not limited to,phototherapeutic modalities, temperature modulation, electricalstimulation, and electro-magnetic fields.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Preferred embodiments of the present invention are illustrated byway of example, and not by way of limitation, in the figures of theaccompanying drawings, in which like reference numerals refer to likecomponents in which:

[0013]FIG. 1A is a lateral view of three normal vertebrae;

[0014]FIG. 1B is a lateral view of three vertebrae wherein the vertebralbody of the middle vertebra is compressed;

[0015]FIG. 2 is a lateral view of a compressed vertebra with bone cementextruded through the fractured vertebral vault;

[0016]FIG. 3 is a top view of a probe including a catheter tube with anexpandable structure in a substantially collapsed condition attached tothe distal end of the catheter;

[0017]FIG. 4A is a lateral view of a transpedicular placement of the arepresentative expandable containment device into a damaged vertebra;

[0018]FIG. 4B is a vertical section through a vertebral bone showing anattached containment device in a substantially collapsed conditionattached to the distal end of a catheter with a severable electrolyticjoint;

[0019]FIG. 5 is a top view of a lumbar vertebra, partially cut away;

[0020]FIG. 6A is a lateral view of one posterior access route to theanterior vertebral body shown in FIG. 1;

[0021]FIG. 6B is a top view of transpedicular and parapedicular routesto the anterior vertebral body; and

[0022]FIG. 7A is a side-view of a self-expanding containment device;

[0023]FIG. 7B is a side-view of the self-expanding containment devicebeing deformed by a ball valve actuator; and

[0024]FIG. 7C is a side-view of the self-expanding containment devicedeformed by the ball valve actuator to assume a concave shape.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Turning to FIG. 1A, the lateral view of typical spinal motionsegments 20 are depicted, with lumbar vertebrae 22, 26, and 28. Incontrast, FIG. 1B illustrates a lateral view of a segment of a spinalcolumn in which the middle vertebra 26′ is compressed. Compression canresult from conditions such as osteoporotic fractures, malignantmetastatic disease, and benign tumors of the bone and are suitable fortreatment using the present invention.

[0026] The percutaneous injection of bone cements, such as PMMA or thelike, in vertebroplasty and kyphoplasty procedures has had some successin the treatment of pain associated with VCFs commonly found inosteoporosis patients. The bone cement is believed to solidify theporous inside and/or potential fractures on the outside of the vertebralbody. When effectively injected, the bone cement is thought to preventpainful motion of the bony segments and to strengthen the spinal columnto prevent further degradation and collapse. Leakage of the bone cementoutside of the preferred treatment zone, however, not only does notalleviate the pain but can also lead to serious side effects. As seen inFIG. 2, where bone cement has extruded through the fractured vertebralvault 30, an exposed, sharp, abrasive, and durable surface 32 may beformed. This extruded media could erode nearby anatomic structures,causing further pain and complications. The precise direction,placement, and containment of therapeutic media and agents isfundamental to optimal patient outcomes. Iatrogenic injury may bereduced or eliminated by the proper application of a containment orchanneling technology. The present invention tends to prevent theunintentional migration of implanted materials, such as bone cement,from the treatment site. This invention, however, is not limited to thetreatment of fractures in the vertebra. The containment device may beutilized in any other bone or soft tissue where it is desired to controleither the release or the unintentional migration of a therapeuticagent. Moreover, it may be utilized to concentrate therapeutic agents atthe treatment site, resulting in their improved biomechanical functionand/or therapeutic effect.

[0027] 1. The Device

[0028] The containment or channeling device of the present invention isa generally hollow or fillable body, that concentrates the focus of thetherapeutic agent and reduces or prevents unintentional migration oftherapeutic materials from the interior of the containment or channelingdevice into tissues or voids that are intended to be preserved. Asdepicted in FIG. 3, one embodiment of the device 84 includes a fillableor expandable body 85 made from a relatively soft, flexible material.The shape of the device will depend upon the therapeutic objectivessurrounding its use and the conformity tolerances of the tissues beingtreated. In many cases, where the wall of the containment or channelingdevice is made from a relatively soft, flexible material, such as afabric or a membrane, the containment device 84 could conform to thecavity inside of the vertebral or other bony body or soft tissue beingtreated. Alternatively, the device may be made of a semi-compliant orrigid material having a pre-determined shape. The containment orchanneling material may be porous, semi-porous, non-porous,bio-resorbable, or non-resorbable. It may be made from a continuousmaterial with uniform properties or it may be interrupted or fenestratedto achieve the treatment objectives. In some instances the materials mayhave a variable thickness or durometer (hardness) to achieve specializedgeometric deployment. For example, a device material may be produced toallow geometric locating or anchoring protrusions from nominal surfacesof the containment device. In addition, self-expanding devices that,rely on the design and biomaterial state of the art may be beneficial insome instances. The specialized properties of memory metals, memorypolymers, and other suitable materials may contribute to the deploymentand/or shaping of such a containment or channeling device.

[0029] Depending on the tissue to be treated and the intendedtherapeutic effect, the containment or channeling device may be manydifferent shapes. Some embodiments may serve a directional orcontainment function by directing, channeling, or concentrating thetreatment media within a specific anatomic orientation or structure orinto a target treatment area. In such a case, the self-expanding devicemay be closed like a “pouch” that can be sealed after filling or openlike a “stent” to channel the material more precisely.

[0030] One particular embodiment may self-expand, similar to a stent,and assume the geometry of a curved column (similar to a sausage casingor linked sausage casings), with either a closed or open end, that couldserve to capture and/or channel the therapeutic media to achieve anoptimal medical outcome. For: example, the physician could carve out acurved void in the anterior region of the vertebral body and then deploythe elongated, curved device into the cavity. Where the device has atleast one open end, e.g., similar to a curved hollow tube, thetherapeutic media would leak out the open ends of the device, cominginto contact with the cancellous bone along the lateral edges of theverteberal body. Although the therapeutic media, e.g., bone cement,would subsequently invade the interstices of the cancellous bone, thecontainment channel would still serve its intended purpose by preventingthe bone cement from entering the venous plexus.

[0031] In another embodiment, as seen in FIG. 7A, the containment orchanneling device 120 may have a bulbous geometry that could bemanipulated to assume alternative shapes as it conforms to the anatomywhere it is inserted. During or after deployment of the device,application of an external force could cause the containment device,which may comprise memory metals or memory polymers, to deformplastically into the shape or space of the tissues that are to betreated. For example, as depicted in FIG. 7C, after filling with thetherapeutic material, the containment device 120 may be collapsed toassume a concave disk-like geometry 120′.

[0032] Another desirable embodiment may be a double (or multiple nested)containment device where there are at least two devices, nested withineach other. In this embodiment, one containment device would surroundthe other and each would be capable of being filled with a therapeuticagent. For example, in the treatment of a soft tissue lesion (e.g.,tumor, etc.), it may be beneficial to have an inner containment devicewith a structural material to provide load-bearing support, whilefilling the outer containment device with a chemotherapeutic agent. Inthis manner, as the lesion responds to chemotherapeutic agent and“shrinks,” the structural material could remain intact to support thetissue that remains.

[0033] Many different delivery devices may be used in conjunction withthe containment or channeling device, enabling the placement of thecontainment device in the proper treatment site. These include, but arenot limited to, a catheter, cannula, needle, syringe, or otherexpandable delivery device. For example, one embodiment of theinvention, as shown in FIG. 3, includes a catheter 78 having a proximalend 80 and a distal end 82. A proximal end 86 of a flexible containmentdevice 84 is attached to the distal end 82 of the catheter 78 in anappropriate manner, e.g., cyanoacrylate glue (or other appropriateadhesive) or construct welded joints (metallic and non-metallic), thatmay best serve any desirable detachment system. These detachment systemsinclude any joint severable by electrolytic, mechanical, hydraulic,photolytic, thermal, or chemical means.

[0034] A wide range of materials can be placed into or, alternatively,coated onto the outside of the containment or channeling device. Bonecement, such as PMMA or the like, could be injected into the containmentdevice 84 to treat compression fractures in the vertebral bodies.Likewise, any number of polymer or liquid formulas, properly containedor channeled, may serve the therapeutic requirements equally well. Thebiomaterial need only be adapted to physiology, which is primarily itsviscoelastic and strength requirements, suited to the fit, form, andfunction of the treated structures and clinical outcome requirements.Where the wall of the containment or channeling device is formed from anon-porous material, the device could prevent the material, e.g., PMMAor epoxy, from “leaking” outside of the vertebra. In the alternative, ifthe wall is formed from a porous material, either rigid or flexible, theimplanted materials may migrate or diffuse away from the containmentdevice into the surrounding area. For example, where the containmentdevice contains large pores, it may be filled with bone cement, such asPMMA or the like, possibly under pressure, until the device reaches itsmaximum capacity. The bone cement may then begin to seep out of thepores to form protrusions in the form of bumps or rods of bone cementextruding in an unorganized manner from the containment device. Inaddition to filling any remaining voids in the cancellous bone of thevertebral body, the extruded spikes may aid in anchoring the containmentdevice in its proper therapeutic place, even if the vertebral body laterchanges shape due to further deterioration. In light of the progressivedeterioration of bones seen in diseases such as osteoporosis and cancer,these extruded rods could provide much needed continued support evenafter the bone resorbs.

[0035] In addition to bone cements, other therapeutic materials may alsobe injected into the containment device. Where the containment device ismade from porous or semi-porous materials, the therapeutic agents mayescape or diffuse through the pores into the surrounding environment.The appropriate degree of porosity or permeability could be determinedin order to achieve the correct dosing and may depend in part on theconcentration of the therapeutic agent and the size of the treatmentsite. Similarly, the containment device may serve as a time-release ordosing vessel in delivering the therapeutic agent where a bio-resorbablematerial, such as poly-lactic acid (PLA), is used. In the treatment offractures, osteoconductive materials, which provide scaffolds on whichnew bones can grow, and osteoinductive materials, which activate stemcells to promote and/or induce bone formation, would be useful intreating compression fractures and enhancing bone growth. Possibletherapeutic materials to be placed in the containment device include,but are not limited to, bone cements and other autogenous tissues orcells, donor tissues or cells, bone substitutes, bone morphogenicproteins (e.g., BMP-2 or OP-1), growth factors (e.g., TGF-β, IGF I, IGFII, and platelet-derived growth factor), tissue sealants,chemotherapeutic agents, and other pharmaceutical agents.

[0036] Depending on the patient's condition, the physician may choose tomodify or accessorize the containment or channeling device as needed.For example, the device may be permanently or temporarily implanted.FIGS. 4A and 4B depict the device 90 inserted: through a hole 67 in thecortical bone 66 of a lumbar vertebra 50. Where the device 90 is to beimplanted in the patient permanently, various detachment technologiesmay be employed after the containment or channeling device andtherapeutic agents are delivered to the proper treatment site.Alternative detachment means may include, but are not limited to,electrolytic detachment; mechanical interference fit (Morse-taper-type,and the like) that can be detached by hydraulic technologies, ballvalves, gas pressure changes; breakaway designs (severable by force orexposure to an alternate internal or external technology); photolyticmeans (severable by exposure to light, laser, and the like); thermalmodulation (heat, cold, and radio frequency); mechanical means(screwing/unscrewing); and bioresorbable technologies (severable byexposure to an aqueous solution such as water, saline, and the like).

[0037] In one embodiment, the containment or channeling device 90 couldbe detached from delivery device 96 using a mechanical interference fitthat can be detached by hydraulic technologies. For instance, a pressurecould be applied by means of a syringe to a mechanically (friction)locked mandrel inside a tube, which is filled with a mechanicallycompatible liquid. The tube could extend from the detachment area to theproximal end of the containment or channeling device 90.

[0038] In another embodiment, the containment or channeling device 90could be detached using thermal or photolytic means. A heat or lightsource at the detachment area could be in contact with the materialconnecting the proximal end of the containment or channeling device 90and the delivery device, melting it to the point of disconnecting thecontainment or channeling device 90. Examples of heat or light sourcesinclude, but are not limited to, a current through a resistance wire, alaser provided through fiber optic means, or the like.

[0039] In another embodiment, the containment or channeling device 90could be detached through mechanical means. This could include variousdesigns of interlocking ends that are held together by a sleeve.Different types of mechanically deployable joints that may be adaptedfor use with the containment′ or channeling device 90 are described inU.S. Pat. Nos. 5,234,437; 5,250,071; 5,261,916; 5,304,195; 5,312,415;and 5,350,397, the entirety of which are herein expressly incorporatedby reference.

[0040] In yet another embodiment, the containment or channeling device90 could be detached from a delivery device 96, such as a braidedcatheter, that is electrolytically conductive. The use ofelectrolytically detachable joints, attached to solid or braided(plurality of filaments) pusher wires, hypotubes, or braided cathetersmay increase physician control during insertion, navigation, deployment,detachment, and retrieval. As seen in FIG. 4B, the proximal end 97 ofthe device 90 could be attached to the distal end 98 of the braidedcatheter 96 in an appropriate manner. For example, a cyanoacrylate glue(or other appropriate adhesive) or a construct welded joint (metallicand non-metallic), may be used to attach the containment or channelingdevice 90 to the distal end 98 of the braided catheter. In general, theentirety of the braided catheter 96 is coated with an insulatingmaterial 102 from its proximal end 100 continuously to theelectrolytically severable junction 104. Insulating material mayinclude, but is not limited to, polytetrafluoroethylene (e.g., Teflon),polyparaxlylene (e.g., parylene), or polyethyleneterrephthalate (PET),polybutylenoterephthalate (PBT), cyanoacrylate adhesives, or othersuitable insulating layers. The electrolytically severable junction 104,devoid of insulating material, is therefore much more susceptible toelectrolysis in an ionic solution such as blood or most other bodilyfluids. The proximal end 100 of the braided catheter 96 may also be leftbare so that a power supply 104 may be attached, which may provide powerfor electrolysis of the joint. The other pole of the power supply istypically attached to a patch on the skin 108 to complete the circuit.After the containment or channeling device is placed in the treatmentarea and filled with a therapeutic agent, the device may be severed fromthe braided catheter used in delivery by the application of a smallelectrical current to the braided catheter 96.

[0041] When necessary, many different methods may be used to seal thecontainment device. In one embodiment, the containment device maycontain a self-sealing one-way valve. In another embodiment, a plug,such as a detachable silicone balloon, may be used to seal the neck ofthe containment device. In the case of the electrolytic detachment usingthe braided catheter, for example, a detachable silicone balloon may beused to plug the catheter distal of the severable joint and proximal tothe containment device. In yet another embodiment, the containmentdevice may adhere to itself where it is made from a material withappropriate adhesive and/or elastic properties, thereby sealing thecontents inside. In addition, where a bone cement such as PMMA or thelike, or a similar substance that solidifies over time, is impregnatedin the containment device, the hardening of the bone cement within thecontainment device after sufficient time has passed obviates the needfor an additional seal. These examples of sealants are not meant to belimiting; any other sealant method known to those who are skilled in theart may be employed to close the containment device and prevent theunintentional migration of its contents from the treatment site.

[0042] Where the device or a portion of the device is only intended tobe implanted temporarily, the device may be collapsed and subsequentlyremoved from the body after the contents of the containment device havesubstantially migrated outside of the device or when it is desired. Inorder to facilitate navigation, detachment, removal, arid implantationof the containment or channeling device, all or portions of the surfacesof the access, delivery, and containment devices may be modified.Surface modifications and methods may include, but not be limited to,ion bombardment, physical vapor deposition plasma coatings,water-soluble neuroprotectant or vascular protectant coatings (heparin,etc.), hydrophilic coatings, anti-adhesion coatings, peptide coatings,gene therapy treatments, anti-corrosion coatings, electricallyinsulating coatings, or other technologies as known in the art. Thesecoatings may prevent further injury to the patient while the device isbeing removed since the coating may decrease the risk of scar tissueforming around the implanted foreign devices. As is well-known to oneskilled in the art, any number of surface modifications may complementthe utility of the device applications and outcomes. In addition,retrievable containment or channeling devices may utilize differentdelivery systems than those used in the case of detachable devices. Inparticular, catheters capable of electrolytic detachment may not bechosen in order to avoid the possibility of accidental detachment due tounintentional exposure of the electrolytic joint to an ionicenvironment.

[0043] In alternative embodiments, additional materials that enhance thedelivery and therapeutic effect of the agents may also be impregnated inthe containment device. These include, but are not limited to,hydrogels, hydrophilic coatings, anti-adhesion media, peptides, andgenes. For example, proteins such as BMP and TGF-β are known to enhancefracture healing, but have short biological half-lives. Therefore,maintaining these proteins at the fracture site in therapeuticconcentrations has been problematic in the past. Delivering genesencoding for a given growth factor in a controlled manner to thefracture site may help overcome this problem. Through the use of aporous, semi-porous, or bio-resorbable containment devices, the genesencoding for BMP or TGF-β could be released into the treatment site andtaken up by recipient cells that might then produce the growth factor atthe fracture site; protein concentrations may then be able to bemaintained for an extended period of time.

[0044] The containment or channeling device may also be combined withdevice or environmental stimulation to provoke or achieve the desireddeployment effect and therapeutic response. For example, some device andenvironmental controls may include, but not be limited to,phototherapeutic modalities, temperature modulation, electricalstimulation, and electro-magnetic fields. For example, where a magnet isimplanted in the containment device, application of a magnetic field maycause the implant to oscillate or may attract a magnetic media to fillthe containment device. Under appropriate conditions, this micromotionmay induce current to flow through the implant, ultimately resulting inenhanced bone growth and/or pain reduction. In an alternativeembodiment, the containment device may be filled or coated with anelectroconductive material associated with a power supply. When combinedwith an external controlling device to communicate with the powersupply, the resulting current may enhance bone growth or other desirabletissue responses.

[0045] 2. Methods of Use

[0046] Although, as noted above, use of the containment or channelingdevice of the present invention is not limited to treatment of vertebralailments, such procedures are discussed here for exemplary purposes.Before discussing such methods of operation, various portions of thevertebra are briefly discussed. FIG. 5 depicts a top view of a vertebra50. At the posterior of the vertebra are a right and left transverseprocess 52R, 52L, a right and left superior articular process 54R, 54L,and a spinous process 56. The right and left lamina, 58R, 58L, lie inbetween the spinous process 56 and the superior articular processes 54R,54L, respectively. A right and left pedicle, 60R; 60L, are positionedanterior to the right and left transverse process, 52R, 52L. A vertebralarch 61 extends between the pedicles 60 and through the lamina 58. Avertebral body 62 is located at the anterior of the vertebra 50 andjoins the vertebral arch 61 at the pedicles 60. The vertebral body 62includes an interior volume of reticulated, cancellous bone 64 enclosedby a compact, cortical bone 66 around the exterior. The vertebral arch61 and body 62 make up the spinal canal, i.e., the vertebral foramen 68;the opening through which the spinal cord and epidural veins pass.

[0047] As shown in FIGS. 4A and 4B, the present invention includes adetachable containment device 90 mounted on a delivery device 96 that isused to position, deploy, and fill the containment device 90. Thephysician can choose from a variety of approaches to insert thecontainment device into the vertebral body. As depicted in FIG. 6A, inthe transpedicular approach 68, access to the cancellous bone 64 in thevertebral body 62 is gained through the pedicle 60. Alternatively, asdepicted in FIG. 6B, a parapedicular approach 72 may be used in whichaccess is gained through the side of the vertebral body 62 beside thepedicle 60. This approach may especially be chosen if the compressionfracture has resulted in collapse of the vertebral body below the planeof the pedicle. Still other physicians may opt for an intercostalapproach through the ribs (not shown) or a more clinically challenginganterior approach (not shown) to the vertebral body.

[0048] The method of the present invention further includes gainingaccess to the interior of the vertebral body 62 through a naturallyoccurring bore or passage 67 in the vertebra formed as a result of thecondition to be treated, as seen in FIG. 4B. Alternatively, a bore orpassage 67 in the bone may be formed with a drill. In the case of aflexible containment or channeling device 90, the size of the bore orpassage 67 into the interior of the vertebral body 62 should be slightlylarger than the external diameter of the implant body in its relaxed orpre-deployed state so that the containment device can be insertedthrough the bore into the vertebral body 62. Alternatively, where thecontainment or channeling device 90 is made from a semi-compliant orrigid material, the size of the bore or passage 67 must be slightlylarger than the size of the external diameter of the semi-compliant orrigid implant. Depending on the level of deterioration of the vertebralbody 62, the depth of the bore or passage 67 may also need to besufficient to allow for the insertion of the full axial length of thedevice 90 into the vertebral body 62. In addition, the physician mayfurther create a cavity 69 within the vertebral body 62 before insertionof the device 90 if desired. This may be accomplished using any surgicaltool to carve out a cavity or perhaps by using an additional expandableor deployable device, such as those used in angioplasty or atraumatictissue expansion or dissection. The containment device is preferablyplaced in the center of the vertebral body void or vault 62 in order todistribute support evenly to the entire structure and to thephysiological loads typical a living organism.

[0049] As discussed before, the containment or channeling device may bedelivered to the treatment site using many different delivery devicesincluding, but not limited to, a catheter, cannula, needle, syringe, orother expandable delivery device. In one embodiment, the containment orchanneling device 90 may be delivered to the treatment site via a guidesheath (not shown) through which the braided catheter 96 with theattached flexible containment or channeling device 90 in a substantiallycollapsed condition, may be pushed through the guide sheath to theinterior of the bony body, the guide sheath having been combined with anobturator or the like, and tunneled through intervening tissue to gainaccess to the treatment site. The guide sheath may be retracted towardsits proximal end, thereby releasing the device 90 into the interior ofthe vertebral body or other treatment site. Many delivery devices andmethods could be employed to deliver the containment device to thetreatment site and are well known to those who are skilled in the art.

[0050] Once the containment device 90 is placed in the proper treatmentarea, it can be filled or deployed in many ways. In one embodiment,wherein the device 90 is made from a flexible material, the device 90may be deployed first in response to temperature change, mechanicalrelease into the tissues, or with a suitable gas, such as carbondioxide, and subsequently be filled with the desired therapeutic agent.For example, where a semi-porous material is used, carbon dioxide at anappropriate pressure may deploy the containment device 90, possiblycreating a cavity within the cancellous bone, depending on the degree ofdeterioration of the vertebral body and the gas pressure used to deploythe containment device 90. The gas may subsequently escape through thepores prior to or while the containment device 90 is filled with thetherapeutic material. The device 90 may also be deployed using anyappropriate mechanical mechanism. This mechanical mechanism may be suchthat the containment device 90 may displace portions of the cancellousbone within the vertebral body upon deployment to create a cavity beforeit is filled with therapeutic materials. Alternatively, the device 90could be filled directly with the therapeutic agent, possibly underpressure.

[0051] Where the containment or channeling device is self-expanding,similar to a stent, upon release from the guide sheath, the containmentdevice may assume its primary shape within the cavity or void in whichit is placed without the aid of any external forces. The device couldsubsequently be filled with the desired therapeutic material.

[0052] In an alternative self-expanding embodiment, the original shapeof the device could be manipulated into another secondary shape with theapplication of an external force. As seen in FIG. 7A, a bulbouscontainment device 120, which includes memory metal or memory polymerthat adds to its shape, is pushed through the distal end of a deliverycatheter 124, here depicted as a braided microcatheter, by a pusher wire128. The containment device 120 contains a one-way ball valve 132 on itsdistal end 134, which can be sealed by the ball valve actuator 136located on the distal end 140 of the pusher wire 128. Under imageguidance, the containment device assembly 118, which includes thecontainment device 120, pusher wire 128, and delivery microcatheter 124,is advanced through the guide sheath (not shown). As the containmentdevice assembly 118 exits the guide sheath (not shown), it is navigatedthrough the tissue or tissue void to be treated. The containment device120 is constrained in its undeployed state within the inner lumen of thebraided microcatheter 124 until final anatomic positioning is achieved.The pusher wire 128 is then advanced, pushing the containment deviceoutside of the braided delivery catheter. As seen in FIG. 7A, thecontainment device, which is made from a self-expanding constructincluding memory metals and/or memory polymers or their performanceequivalent, expands into the anatomy to be treated.

[0053]FIG. 7B depicts the shaping process of the containment device 120as the ball actuator 136 engages the dome 122 of the containment device120. The pusher wire 128, with its ball actuator 136, is used to beginthe shaping of the device by applying a retrograde motion, as if towithdraw the pusher wire 128 from the delivery microcatheter 124. As thepusher wire 128 is pulled, the ball actuator 136 engages the bail valve132 at the distal end 134 of the dome 122 of the containment device 120.The force of this motion plastically deforms the dome 122 of thecontainment device 120, pulling it towards the equator 123 of thecontainment device 120, ultimately to reshape the containment device 120into a concave geometry, appropriate to the anatomy to be treated. Othermeans to deform or shape the device include, but are not limited to,changes in temperature or the application of an electrical or magneticfield.

[0054] The net effect of this action, as seen in FIG. 7C, is to deformthe armature 126 sufficient to permanently remodel the containmentdevice 120′ geometry in a manner that improves the acceptance of thebiomaterial or pharmaceutical agent and ultimately the therapeuticoutcomes. The dome 122 of the containment device 120 has been drawn intoits base. The armature 126 has reached its plastic deformation pointwithout compromise to the ability of the containment device to containany therapeutic media. The remodeled shape of the containment device(disk-like or bowl-like shape) may enable the treatment of tissues thatbenefit from this shape alternative.

[0055] In addition, other ailments, which are not specific to bone, mayalso be treated with the present invention. For example, in the case ofcancer, whether it be in the bone or soft tissue, placement of acontainment device into or near the tumor could allow for the deliveryof chemotherapeutic agents directly to the tumor. Where the containmentdevice is made from porous, semi-porous, or bio-resorbable material, thechemotherapeutic agents contained within the containment device may beable to diffuse to the surrounding area. The containment device may beplaced inside of a tumor using an appropriate interventional technique.For examples, a guide sheath may be used to tunnel through adjacenttissue. The containment device may then be inserted into the desiredtherapeutic site through the guide sheath. When necessary, thecontainment device may be attached to the soft tissue. Sutures, or othermethods that are well known to those who are skilled in the art, may beused to stabilize the placement of the containment device. Possiblechemotherapeutic agents include, but are not limited to, cisolatin,doxcrubicin, daunorubicin, methotrexate, taxol, and tamoxifen. And inthe case of deep wounds, the containment device may be used to deliverantibodies to the site. Additionally, it is conceivable that, myofascialpain syndrome, which is a condition of the tissues characterized byintense localized pain coming from muscles and their respectiveconnective tissues, could also be treated. A containment device madefrom porous, semi-porous, or bio-resorbable material may be placed inbetween the muscle fascia, providing for the controlled release ofmuscle relaxants and other therapeutic agents that may help to treat thesyndrome as the therapeutic agents diffuse away from the containmentdevice. Plantar Fasciitis, which is an inflammation of the plantarfascia tissue at its attachment to the heel bone, could also be treatedthrough placement of the containment device near the plantar fascia (atough, fibrous band of connective tissue that extends over the sole ofthe foot). Similar to the above examples, the containment device mayprovide for the controlled delivery of anti-inflammatory drugs and othertherapeutic agents that may provide relief from the acute painassociated with the condition.

[0056] While the invention is susceptible to various modifications andalternative forms, specific examples thereof have been shown in thedrawings and are herein described in detail. It should be understood,however, that the invention is to cover all modifications, equivalents,and alternatives falling within the scope of the appended claims.

What is claimed is:
 1. A medical containment device for use in a bonybody comprising: a generally hollow body conformable to an interiorcavity of a bony body having an opening through which a therapeuticmaterial may be inserted, the generally hollow body providing a barrierpreventing the unintentional migration of the therapeutic material fromthe interior of the generally hollow body; and a delivery device toconvey the generally hollow body into an interior of a bony body throughan opening in the bony body, wherein the generally hollow body isattached to a distal end of the delivery device.
 2. The medical deviceof claim 1, wherein the generally hollow body is made from a flexible orconformable material, sufficient to achieve optimal anatomic fit andclinical function.
 3. The medical device of claim 1, wherein thegenerally hollow body has a pouch shape.
 4. The medical device of claim1, wherein the generally hollow body contains a therapeutic material. 5.The medical device of claim 4, wherein the therapeutic material is abone cement.
 6. The medical device of claim 5, wherein the bone cementseals the containment device.
 7. The medical device of claim 1, whereinthe deliver device is a catheter.
 8. The medical device of claim 1,further comprising a system to monitor healing and/or stimulatetherapeutic responses.
 9. The medical device of claim 1, wherein thegenerally hollow body is detachable from the delivery device.
 10. Themedical device of claim 9, wherein the delivery device comprises aseverable junction adapted to dissolve upon exposure to an aqueousenvironment.
 11. A medical containment device for use in a vertebralbody comprising: a generally hollow body having an opening through whicha bone cement may be inserted, the generally hollow body providing abarrier preventing the unintentional migration of the bone cement fromthe interior of the containment device; and a delivery device to conveythe generally hollow body into an interior of a bony body through anopening in the bony body, wherein the generally hollow body is attachedto a distal end of the delivery device.
 12. The medical device of claim11, wherein the generally hollow body contains a therapeutic material.13. The medical device of claim 12, wherein the therapeutic material isa bone cement.
 14. The medical device of claim 11, wherein the generallyhollow body has a pouch shape.
 15. The medical device of claim 11,wherein the generally hollow body is detachable from the deliverydevice.